Logical unit numbers for Fibre Channel ports

The Lenovo Storage V7000 system supports a maximum of 2048 logical unit numbers (LUNs) per I/O group, with a maximum of 2048 LUNs configured to any one host.

Each volume that is created on the Lenovo Storage V7000 system can be mapped to multiple HBA Fibre Channel ports in a given host. There can also be multiple paths across the SAN. For these reasons, each host must run multipathing software, such as the subsystem device driver (SDD). The multipathing software manages the many paths that are available to the volume and presents a single storage device to the operating system. The Lenovo Storage V7000 system supports various multipathing software. The specific multipathing software that is supported by the Lenovo Storage V7000 system depends on the host operating system with which it is being used.

• The number of paths through the network from the Lenovo Storage V7000 system nodes to a host must not exceed eight. Configurations in which this number is exceeded are unsupported.
  • Each Lenovo Storage V7000 system node has multiple ports and each I/O group has two Lenovo Storage V7000 system nodes. Therefore, without any zoning, the number of paths to a volume is the number of Lenovo Storage V7000 ports in the I/O group times the number of host ports.
  • This rule exists to limit the number of paths that must be resolved by the multipathing device driver.

If you want to restrict the number of paths to a host, zone the switches so that each HBA port is zoned with one Lenovo Storage V7000 system port for each node in the clustered system. If a host has multiple HBA ports, zone each port to a different set of Lenovo Storage V7000 system ports to maximize performance and redundancy.

For directly-attached host HBA ports there must be a connection to each Lenovo Storage V7000 system node that has volumes mapped to that host.